scholarly journals Are Elevation and Open‐Water Conversion of Salt Marshes Connected?

2020 ◽  
Vol 47 (3) ◽  
Author(s):  
Neil K. Ganju ◽  
Zafer Defne ◽  
Sergio Fagherazzi
Keyword(s):  
Salt Marshes ◽  
Open Water

scholarly journals A COMPARISON BETWEEN GERMAN AND NORTH AMERICAN TIDAL INLETS

1988 ◽  
Vol 1 (21) ◽  
pp. 199
Author(s):  
Reinhard Dieckmann ◽  
Manuela Osterthun ◽  
Hans Werner Partenscky
Keyword(s):  
Salt Marshes ◽  
Morphological Structure ◽  
Open Water ◽  
Coastal Structures ◽  
Tidal Inlets ◽  
Cross Sectional ◽  
Short Account ◽  
Shaping Process ◽  
Geomorphological Parameters ◽  
Good Agreement

Initial results are presented relating to an investigation of geomorphological parameters from 26 of a total of 28 tidal inlets and 11 coastal structures similar to inlets along the German Bight. The following parameters were investigated: - tidal prism - inlet area relationship, - cross-sectional form and depth, - location of the channel within the cross-section, - ebb tidal deltas and - the structures of the back barrier regions. The most important parameter governing the shaping process of these coastal structures is considered to be the tidal volume. The results of the investigations were compared with data from American publications. Despite the differences between the regions studied, in overall terms, surprizingly good agreement was obtained between the parameters investigated. Notable differences exist only in relation to the morphological structure of the back barrier regions (tidal flats, salt marshes, open water lagoons). In respect of the latter differences, a short account is given of the biological and climatological influencing factors.

scholarly journals The Life and Death and Consequences of Canals and Spoil Banks in Salt Marshes

Wetlands ◽  
2020 ◽  
Vol 40 (6) ◽  
pp. 1957-1965 ◽  
Author(s):  
R. Eugene Turner ◽  
Erick M. Swenson
Keyword(s):  
Salt Marshes ◽  
Soil Compaction ◽  
Life Time ◽  
Open Water ◽  
Mineral Matter ◽  
Vegetative Cover ◽  
Morphometric Measurements ◽  
Life And Death ◽  
Spoil Bank ◽  
Spoil Banks

AbstractWe describe the consequence and demise of levees (spoil banks) built from dredging canals in Louisiana salt marshes using morphometric measurements made over 30 years, soil collections on the spoil bank and in the salt marshes behind, and complementary observations from other areas. These measurements were used to determine the temporal bounds of how long spoil banks last and if salt marsh soils remaining in salt marshes are affected. If the rates of changes in spoil bank morphology continue, then the estimated life time of the shrub-tree vegetation at a representative spoil bank is 81 years, the spoil bank width is 89 years, and the dredged channel will erode to the center of the spoil bank after 118 years. The soils in marshes behind the spoil bank have a higher bulk density than in reference marshes, accumulate more mineral matter per year, have lower root mass and are weaker. These observations are compatible with measurements of spoil bank width, vegetative cover and soil compaction, and the conversion from wetland to open water on a coastwide scale.

scholarly journals Buying Time with Runnels: a Climate Adaptation Tool for Salt Marshes

2022 ◽  
Author(s):  
Alice F. Besterman ◽  
Rachel W. Jakuba ◽  
Wenley Ferguson ◽  
Diana Brennan ◽  
Joseph E. Costa ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Climate Adaptation ◽  
Open Water ◽  
Tidal Range ◽  
Management Interventions

AbstractA prominent form of salt marsh loss is interior conversion to open water, driven by sea level rise in interaction with human activity and other stressors. Persistent inundation drowns vegetation and contributes to open water conversion in salt marsh interiors. Runnels are shallow channels originally developed in Australia to control mosquitoes by draining standing water, but recently used to restore marsh vegetation in the USA. Documentation on runnel efficacy is not widely available; yet over the past 10 years dozens of coastal adaptation projects in the northeastern USA have incorporated runnels. To better understand the efficacy of runnels used for restoration, we organized a workshop of 70 experts and stakeholders in coastal resource management. Through the workshop we developed a collective understanding of how runnels might be used to slow or reverse open water conversion, and identified unresolved questions. In this paper we present a synthesis of workshop discussions and results from a promising case study in which vegetation was restored at a degraded marsh within a few years of runnel construction. Despite case study outcomes, key questions remain on long-term runnel efficacy in marshes differing in elevation, tidal range, and management history. Runnel construction is unlikely to improve long-term marsh resilience alone, as it cannot address underlying causes of open water conversion. As a part of holistic climate planning that includes other management interventions, runnels may “buy time” for salt marshes to respond to management action, or adapt to sea level rise.

scholarly journals Resistance, resilience, and recovery of salt marshes in the Florida Panhandle following Hurricane Michael

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katherine A. Castagno ◽  
Tori Tomiczek ◽  
Christine C. Shepard ◽  
Michael W. Beck ◽  
Alison A. Bowden ◽  
...  
Keyword(s):  
Salt Marshes ◽  
Open Water ◽  
Aerial Imagery ◽  
Marsh Management ◽  
Private Land ◽  
Policy And Practice ◽  
Private Lands ◽  
Coastal Salt Marshes ◽  
Florida Panhandle ◽  
Vegetation Loss

AbstractCharacterizing the fragility, resistance, and resilience of marshes is critical for understanding their role in reducing storm damages and for helping to manage the recovery of these natural defenses. This study uses high-resolution aerial imagery to quantify the impacts of Hurricane Michael, a category 5 hurricane, on coastal salt marshes in the Florida Panhandle, USA. Marsh damage was classified into several categories, including deposition of sediment or wrack, fallen trees, vegetation loss, and conversion to open water. The marshes were highly resistant to storm damages even under extreme conditions; only 2% of the 173,259 km2 of marshes in the study area were damaged—a failure rate much lower than that of artificial defenses. Marshes may be more resistant than resilient to storm impacts; damaged marshes were slow to recover, and only 16% of damaged marshes had recovered 6 months after landfall. Marsh management mattered for resistance and resilience; marshes on publicly-managed lands were less likely to be damaged and more likely to recover quickly from storm impacts than marshes on private land, emphasizing the need to incentivize marsh management on private lands. These results directly inform policy and practice for hazard mitigation, disaster recovery, adaptation, and conservation, particularly given the potential for more intense hurricane landfalls as the climate changes.

The M/V New Amity Response: Balancing Safety, Environment, and Commerce During an Emergency Oil Spill Response

2003 ◽  
Vol 2003 (1) ◽  
pp. 1103-1107
Author(s):  
Kevin Cook ◽  
Richard Arnhart ◽  
Charlie Henry
Keyword(s):  
Oil Spill ◽  
Homeland Security ◽  
Salt Marshes ◽  
Terrorist Attack ◽  
Container Terminal ◽  
Open Water ◽  
Coast Guard ◽  
Worker Safety ◽  
Estuarine System ◽  
Environmental Response

ABSTRACT On 22 September 2001, a collision occurred between the M/V NEW AMITY and barge, NMS No. 1486 in the Houston Ship Channel. The collision resulted in damage to a single skinned fuel tank of the NEW AMITY and created an oil spill in Upper Galveston Bay near Morgans Point, Texas. The double-hulled cargo oil tanks on the NEW AMITY were not damaged. Additionally, none of the tanks on the NMS No. 1486 were damaged. Immediately after the incident, the damaged tanker was directed by the Coast Guard Captain of the Port (COTP) and Federal On-Scene Coordinator (FOSC) to proeceed to the nearest lay berth. The Port of Houston Barbours Cut container terminal was less that a mile away and the tanker arrived while still leaking oil. A reported 36,000 gallons of IFO-380 was released before the source could be controlled; much of the oil being trapped under the pier structures within Barbours Cut. The oil spill impacted some 20 miles of shoreline habitat including salt marshes, sand and shell beaches, and riprap. The decision to move the vessel into Barbours Cut set the stage for a challenging, but ultimately successful spill response and cleanup. It was uniquely characterized by the difficult task of balancing safety, environmental, and commercial concerns during spill response. Response actions were conducted with the goal of minimizing impacts to commerce without compromising the environmental response and worker safety. The Shoreline Cleanup and Assessment Team (or SCAT) process was used to insure that environmental issues were addressed with participation of trustee agencies and to develop cleanup endpoints. Considering the volume of oil released into a sensitive estuarine system, the long-term impacts to the environment were relatively minor. To expedite cleanup, the entire 1.1 mile overhanging dock facility was cleared and four tugs were used to provide a unique method to flush oil out from under the dock into collection areas and open water mechanical skimming systems. Additionally, surface washing agents were used to enhance vessel and hard structure cleanup. Despite the extended response and difficult conditions, no major injuries were reported during the response. A complicating factor throughout was that the spill occurred just eleven days after the September 11th terrorist attack, as U.S. Coast Guard resources and local media were focused on maritime homeland security.

scholarly journals Salt Marsh Elevation Limit Determined after Subsidence from Hydrologic Change and Hydrocarbon Extraction

2020 ◽  
Vol 13 (1) ◽  
pp. 49
Author(s):  
R. Eugene Turner ◽  
Yu Mo
Keyword(s):  
Salt Marshes ◽  
Oil And Gas ◽  
Plant Cover ◽  
Plant Stress ◽  
Open Water ◽  
Marsh Surface ◽  
Production Site ◽  
Hydrologic Change ◽  
Hydrocarbon Removal ◽  
High Production

Levee construction aboveground and hydrocarbon removal from belowground in coastal wetlands can create hydrologic changes that increase plant stress through flooding. But the significance of the subsidence they cause individually or in combination is contested. This study untangled them to demonstrate elevational limits of salt marshes by studying dredged and natural waterways in two salt marshes in Louisiana, USA. The areas had a homogenous plant cover before drilling for oil and gas extraction peaked in the 1960s, and now are a mixed network of natural waterways and dredged canals used to drill wells with an average drill date of 1965.8 ± 2.7 (µ ± 1 SEM; n = 18) and well depth of 4661.0 m ± 56.6 (µ ± 1 SEM; n = 18). Aerial imagery was used to document how canals widened to become 2 to 4 times larger than their original construction width at the high production site and 50% larger at the low production site, whereas increases at the nearby natural channels were much less. Light detection and ranging (LIDAR) measurements at the high production site from 2002 showed that the marsh surface near wells subsided by 34 cm compared to undredged sites. Elevation in marshes at producing and dry wells were equal at the low production site, but high production well locations were even lower than at dry wells. An elevation vs. percent open water curve developed from these data overlapped with an independent analysis of a brackish marsh. A relative subsidence rate between 7.4 to 10.4 mm y−1 transformed these salt marshes to an open water habitat within a few decades. The local creation of accommodation space through hydrocarbon removal and leveed wetlands is a parsimonious explanation for the spatial and temporal land loss rates on this deltaic coast over the last 80 years of oil and gas exploration. Substantial losses from the accelerating rates of sea level rise are indicated to occur before 2050.

scholarly journals Ecosystem Metabolism Modulates the Dynamics of Hypoxia and Acidification Across Temperate Coastal Habitat Types

2021 ◽  
Vol 8 ◽  
Author(s):  
Ryan B. Wallace ◽  
Bradley J. Peterson ◽  
Christopher J. Gobler
Keyword(s):  
Salt Marsh ◽  
Spatial Variability ◽  
Salt Marshes ◽  
Dissolved Inorganic Carbon ◽  
Open Water ◽  
Ecosystem Metabolism ◽  
Total Alkalinity ◽  
Seagrass Meadows ◽  
Marine Habitats ◽  
Estuarine Site

Changes in photosynthetic and respiration rates in coastal marine habitats cause considerable variability in ecosystem metabolism on timescales ranging from diel to tidal to seasonal. Here, temporal and spatial dynamics of dissolved oxygen (DO), carbonate chemistry, and net ecosystem metabolism (NEM) were quantified from spring through fall in multiple, distinct, temperate estuarine habitats: seagrass meadows, salt marshes, an open water estuary, and a shallow water habitat dominated by benthic macroalgae. DO and pHT (total scale) measurements were made via high frequency sensor arrays coupled with discrete measurements of dissolved inorganic carbon (DIC) and high-resolution spatial mapping was used to document intra-habitat spatial variability. All habitats displayed clear diurnal patterns of pHT and DO that were stronger than tidal signals, with minimums and maximums observed during early morning and afternoon, respectively. Diel ranges in pHT and DO varied by site. In seagrass meadows and the open estuarine site, pHT ranged 7.8–8.4 and 7.5–8.2, respectively, while DO exceeded hypoxic thresholds and aragonite was typically saturated (ΩAr > 1). Conversely, pHT in a shallow macroalgal and salt marsh dominated habitats exhibited strong diel oscillations in pHT (6.9–8.4) with diel acidic (pHT < 7) and hypoxic (DO < 3 mg L–1) conditions often observed during summer along with extended periods of aragonite undersaturation (ΩAr < 1). The partial pressure of carbon dioxide (pCO2) exceeded 3000 and 2000 μatm in the salt marsh and macroalgal bed, respectively, while pCO2 never exceeded 1000 μatm in the seagrass and open estuarine site. Mesoscale (50–100 m) spatial variability was observed across sites with the lowest pHT and DO found within regions of more restricted flow. NEM across habitats ranged from net autotrophic (macroalgae and seagrass) to metabolically balanced (open water) and net heterotrophic (salt marsh). Each habitat exhibited distinct buffering capacities, varying seasonally, and modulated by adjacent biological activity and variations in total alkalinity (TA) and DIC. As future predicted declines in pH and DO are likely to shrink the spatial extent of estuarine refuges from acidification and hypoxia, efforts are required to expand seagrass meadows and the aquaculture of macroalgae to maximize their ecosystem benefits and maintain these estuarine refuges.

Urbanization impacts on production and recruitment of Fundulus heteroclitus in salt marsh creeks

2020 ◽  
Vol 645 ◽  
pp. 187-204
Author(s):  
PJ Rudershausen ◽  
JA Buckel
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Fundulus Heteroclitus ◽  
Multiple Factor Analysis ◽  
Southeastern Usa ◽  
Density Dependent ◽  
Dependent Relationship ◽  
Juvenile Abundance ◽  
The Relationship ◽  
Throw Trap

It is unclear how urbanization affects secondary biological production in estuaries in the southeastern USA. We estimated production of larval/juvenile Fundulus heteroclitus in salt marsh areas of North Carolina tidal creeks and tested for factors influencing production. F. heteroclitus were collected with a throw trap in salt marshes of 5 creeks subjected to a range of urbanization intensities. Multiple factor analysis (MFA) was used to reduce dimensionality of habitat and urbanization effects in the creeks and their watersheds. Production was then related to the first 2 dimensions of the MFA, month, and year. Lastly, we determined the relationship between creek-wide larval/juvenile production and abundance from spring and abundance of adults from autumn of the same year. Production in marsh (g m-2 d-1) varied between years and was negatively related to the MFA dimension that indexed salt marsh; higher rates of production were related to creeks with higher percentages of marsh. An asymptotic relationship was found between abundance of adults and creek-wide production of larvae/juveniles and an even stronger density-dependent relationship was found between abundance of adults and creek-wide larval/juvenile abundance. Results demonstrate (1) the ability of F. heteroclitus to maintain production within salt marsh in creeks with a lesser percentage of marsh as long as this habitat is not removed altogether and (2) a density-dependent link between age-0 production/abundance and subsequent adult recruitment. Given the relationship between production and marsh area, natural resource agencies should consider impacts of development on production when permitting construction in the southeastern USA.

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